Lecture 7

Book Recommended and Referred for this Lecture: Introduction to computers, 6th Edition by Peter Norton
Note: This book is available online in pdf on this link ---> Download Book

INTRODUCTION TO INFORMATION TECHNOLOGY

Definition of IT:

“Information technology (IT) is a technology which uses computers to gather, process, store, protect, and transfer information” (IT Desk, 2011).

Today, it is common to use the term Information and communications technology (ICT) because it is unimaginable to work on a computer which is not connected to the network.

Definition of Computer

“Computer is an electronic device that processes data, converting into information that is useful to people” (Peter Norton, 2008)

Types of Computers:

Primarily computers are of six types which are as follows;

1.     Desktop Computers.

2.     Workstations.

3.     Notebook Computers.

4.     Tablet Computers.

5.     Handheld Computers.

6.     Smart Phones.

Computer System:

A complete “Computer System” consists of four components;

1.     Hardware

2.    Software

3.     Data

4.     User

1.      Hardware: The mechanical devices that make up the computer are called hardware. They tangible and visible (Eg: Monitor, Keyboard, printer etc)

2.      Software:  It is set of instructions that make the computer perform tasks. In other words, software tells the computer what to do. The term program refers to any piece of software.

3.      Data: It consists of individual facts or pieces of information that by themselves may not make much sense to a person. A computer’s primary job is to process these tiny pieces of data in various ways, converting them into useful information.

4.      User: User is the computer operator who uses computer or operates the computer.

The Information Processing Cycle:

Computer converts data into information by performing various actions on the data. A computer performs a mathematical operation on two numbers, and then displays the result. Or computer might perform a logical operation such as computing two numbers then display that result. These operations are part of a process called Information Processing Cycle comprising of following four parts.

1.     Input: In this part computer accepts data from various sources for  processing.

2.     Processing: In this, processing components perform actions on the accepted data based on instructions (from user or program).

3.     Output: In this, computer displays the result of processed data through output device i.e. monitor.

4.     Storage: In this step, computer permanently stores the results of its processing on the disk.

Computer Hardware:

In a personal computer, hardware devices fall into following four categories.

1.     Processor

2.     Memory

3.     Input and output (I/O)

4.     Storage

1.     Processor: It is like brain of the computer also known as the CPU, or "central processing unit." It handles all the basic system instructions, such as processing mouse and keyboard input and running applications.

2.     Memory: it is one or more set of chips that store data and program instructions, either temporarily or permanently. Computer uses two types of memory; RAM and ROM.

a.     RAM (Random Access Memory) is a container for programs that are currently running and data that is being processed. RAM is called volatile memory because it stores data temporarily which vanishes when computer gets switched off.

b.     ROM (Read Only Memory) is a memory that stores the data permanently even when computer is shut off. ROM also called non-volatile memory.

3.     Input and output (I/O)

Allows the user to interact

a.     Input devices accept data.

Ex: Keyboard, mouse etc.

b.     Output devices deliver data.

Ex: Monitor, printer, speaker etc.

c.      Some devices are input and output both.

Ex: Touch screens

4.     Storage

A computer needs a place to keep program files and related data when they are not in use. The purpose of storage is to hold data permanently, even when the computer is turned off.

There are two main types of computer storage:1.     Magnetic Storage.

2.     Optical Storage.

Magnetic Storage uses magnetic coated layer for storing data. Hard Disk Drive -HDD- device (memory) used for permanent data storage. Data is stored on magnetic platters; electromagnetic heads are used for reading and recording data with the exception of the newest disk types called Solid State Drive (SSD). The floppy disk has now become obsolete and flash drives (USB Data Travelers) are commonly used which are not magnetic storage.

Optical storage devices that uses lasers to read data from or write data to the reflective surface of an optical disc. CD ROM, CD –R, CD RW, DVD etc are common examples of optical storage.